Generating electricity without the use of fossil fuels is not just an engineering and industrial challenge, it is also a huge mathematical challenge.

Producing electricity securely, safely, reliably and cheaply, has many challenges. Chris Budd explains that the answer to many of these issues is maths.

Producing electricity securely, safely, reliably and cheaply has many challenges. Chris Budd explains that the answer to many of these issues is maths.

When the mathematician AK Erlang first used probability theory to model telephone networks in the early twentieth century he could hardly have imagined that the science he founded would one day help solve a most pressing global

problem: how to wean ourselves off fossil fuels and switch to renewable energy sources.

Find out how to beat the world record in stone skimming - you just need to do the maths!

Astronomer Royal **Sir Martin Rees** gives *Plus* a whistlestop tour of some of the more extraordinary features of our cosmos, and explains how lucky we are that the universe is the way it is.

Have you ever noticed what happens when you spin a coin on a table? As the coin starts to fall over and roll on its edge, its spin gets faster and faster until it suddenly stops altogether.

What is light? Sometimes it seems wave-like and sometimes particle like. See how Einstein applied his theory of relativity to the problem, predicted that photons have no mass and laid the foundations for quantum mechanics.